<script type="text/javascript" src="<?php echo base_url(); ?>tablesorter/jquery-latest.js"></script> 
<script type="text/javascript" src="<?php echo base_url(); ?>tablesorter/jquery.tablesorter.js"></script> 

<?php echo $tablesorter; ?>

<script type="text/javascript">
$(function(){
	$("#tb").tablesorter(); 
});
</script>